More than 200 prominent international authors, including Günter Grass, Salman Rushdie, Margaret Atwood and Jonathan Franzen, have joined forces to denounce the "chokehold" they say Russia's anti-gay and blasphemy laws place on the freedom of expression, amid a growing swell of protest on the eve of the opening of the Sochi Winter Olympics.

The authors' open letter, published in the Guardian on Thursday, comes as athletes and journalists from around the world descend on the Black Sea resort before the lavish opening ceremony at a specially built stadium on Friday evening. President Vladimir Putin has spoken of the Games as a personal project to show the world Russia's greatness and its ability to host such major events, but the build-up has been marred by controversy over corruption and rights abuses in Russia.

The open letter to Russia condemns the recently passed gay propaganda and blasphemy laws, which respectively prohibit the "propaganda of non-traditional sexual relations" among minors and criminalise religious insult, as well as the recent recriminalisation of defamation. The three laws "specifically put writers at risk", say the authors, and they "cannot stand quietly by as we watch our fellow writers and journalists pressed into silence or risking prosecution and often drastic punishment for the mere act of communicating their thoughts".

Grass is joined as a signatory by three fellow Nobel laureates, Wole Soyinka, Elfriede Jelinek and Orhan Pamuk, and by acclaimed writers from over 30 countries, including Ariel Dorfman, Carol Ann Duffy, Edward Albee, Julian Barnes, Ian McEwan and Neil Gaiman. Russia's foremost contemporary novelist, Lyudmila Ulitskaya, is also a signatory to the letter.

Rushdie described the campaign as essential, telling the Guardian that it is "incredibly important to Russian writers, artists and citizens alike".

"The chokehold that the Russian Federation has placed on freedom of expression is deeply worrying and needs to be addressed in order to bring about a healthy democracy in Russia," said the Booker prize-winning novelist, author of Midnight's Children and The Satanic Verses.

Gaiman said: "I believe that free expression – freedom of speech, freedom to write, to argue, to disagree – is the most important freedom we have as human beings. I hate to see that being stifled in Russia. The solution to speech and writing that offends you is to speak and write about it in your turn, not to criminalise it or to try and eradicate it.

"Criminalising those who write positively about gay people and gay themes, or who write negatively about the church, criminalising defamation, these are all things that clamp down on the exchange of ideas, that push dissent and stories underground. I hope that Mr Putin reads the open letter; I hope he changes course."

Ulitskaya, the first woman to win the Russian equivalent of the Booker, said that Russian authorities were attempting to impose "a cultural ideology that, in many respects, mimics the style of Soviet-era propaganda".

"Like many Russian citizens, I am deeply concerned about the increasing restrictions on freedom of speech in my country, about the ever-expanding legislation and arbitrary bureaucracy that affect all aspects of Russian life," she said. "I am frightened by the judicial system's increasing dependence on these very authorities. Because of this, I signed PEN International's open letter to the Russia authorities protesting their increasingly regressive approach to freedom of expression."The tension is not only being felt in the literary world. In the past week, the only independent source of television news in Russia, cable station TV Rain, has been cut off from its viewers, after all the main cable providers dropped it from their broadcasts.

The ostensible reason is offence caused after a poll on the channel's website about whether the Soviets should have given up Leningrad during the second world war, but editors say cable companies have admitted in private that they acted after receiving phone calls from the presidential administration.

In another sign that the already squeezed media landscape is set to narrow further, the leading state news agency RIA Novosti, which was known for its relatively impartial coverage of events in Russia, has also been "liquidated" according to Kremlin decree, in changes that will fully come into effect after it has finished covering the Olympics.

The gay law in particular has caused international outcry. Putin claimed last month that it was not discriminatory, but aimed at protecting Russian children from dangerous information about homosexuality and paedophilia. He said gay people were welcome to visit Sochi as long as they "leave children alone".

The gay advocacy group All Out organised protests against the law in 19 cities worldwide on Wednesday, and has also released a list of athletes, including 12 who will compete at these Olympics, who are calling on Russia to change the law. However, the athletes are under pressure from the International Olympic Committee not to make any statements deemed as "political" during the Games, and so many are treading carefully.

The 217 authors who signed the open letter are urging the Russian authorities to repeal these laws, which they say "strangle free speech".

They also want Russia to recognise its obligation under the international covenant on civil and political rights "to respect freedom of opinion, expression and belief – including the right not to believe – and to commit itself to creating an environment in which all citizens can experience the benefit of the free exchange of opinion". The letter adds: "A healthy democracy must hear the independent voices of all its citizens; the global community needs to hear, and be enriched by, the diversity of Russian opinion."

The letter is part of PEN International's worldwide campaign to highlight what it calls "the draconian restrictions placed on free expression" in Russia since Vladimir Putin returned to office in May 2012.

Although the writers' organisation welcomed December's release of 2,000 prisoners – including two members of Pussy Riot and the Arctic 30 environmental protesters – it said they should never have been arrested in the first place, and called the amnesty "part of a politically motivated move to soothe criticism ahead of the Sochi Games during which a huge wave of protest is expected in Russia and beyond in response to Putin's increasingly repressive approach to freedom of expression".

Even after the amnesty, other controversial cases have continued. In Moscow on Wednesday, the remaining eight defendants in a lengthy court case against protesters who clashed with police the day before Putin's inauguration in 2012 gave their "last word". They are accused of "causing mass riots" and face up to six years in prison, in a case that many have seen as politically ordered so as to discourage protests.

Separately, two environmental activists who have written about abuses in the run-up to the Olympics in Sochi have been arrested this week on what have been called trumped-up charges by Amnesty International.